This invention relates to a dual fluid swivel joint connector having a quick disconnectable coupling for uncoupling and shutting flow of at least one of the fluids therethrough, and more particularly to a swivel joint connector for mounting in a liquid fuel supply line of a fuel dispensing station having a vapor return line, the swivel joint permitting a dispensing nozzle to pivot relative to the fuel and vapor lines or permitting a first section of the lines to pivot relative to another section, and having detachable means which quickly decouples to shut flow communication of at least the fuel at the joint when the tensile load at the joint is above a predetermined level. The invention is additionally directed to a detachable coupling wherein the tensile force due to a pulling on the line, and the hydrostatic forces of the fuel within the coupling are resisted independently and are not cumulative in the coupling, whereby the uncoupling occurs solely as a result of excessive tensile load.
It is known in the fuel dispensing art to include a swivel connector at the dispenser/hose interface so that twisting loads applied to the dispenser are not transmitted to the hose resulting in twisting thereof. Such swivels merely permit the dispenser, such as a fuel dispensing nozzle, to be pivoted about one or more axes relative to the axis of the hose, the swivel permitting flow communication means between the hose and the dispensing device.
Additionally, it is known to utilize quick disconnect or breakaway couplings in the fuel line spaced from the dispenser so that if a vehicle is driven away from the fuel dispensing station before the dispensing nozzle is removed from the filler neck of the vehicle, an uncoupling will result, shutting the flow of fuel and preventing the volatile fuel to be spilled due to either a dislodging of the moorings of the fuel dispensing station, breakage of the hose, or other failure of the fuel dispensing system. The prior art has proposed a number of decouplers which are actuated by a tensile force in the line. In our aforesaid copending application serial No. 07/107,947, the problems and deficiencies of the prior art decoupler units are described and combination swivel joint and quick disconnect coupling devices are disclosed and claimed, the devices having coupling means between first and second body members which swivel relatively to one another and the coupling means acting normally to connect the body members in flow communication and for decoupling when an external tensile force above a predetermined level is applied to the fuel line, and valving acting for shutting flow communication when the body members are decoupled. These coupling devices also included devices having means for resisting the hydrostatically generated forces of the fuel and for resisting the spike line pressure shock forces resulting when the nozzle is snapped shut independently of the means for resisting the tensile forces resulting from line pull so that the hydrostatic forces, the spike pressure forces and the tensile forces would not be cumulative as in the prior art.
However, certain fuel dispensing stations may include, and in certain jurisdictions are required to include, a vapor return system for venting or drawing off the vapors while fuel is dispensed and return the vapors to the storage tank. This prevents the combustible vapors from being discharged into the atmosphere so as to protect against fire hazards and environmental contamination. In these systems the vapor flows in a counter-flow direction relative to that of the fuel, and the fuel conduit, including the nozzle, has two separate concentric or coaxial passageways, one for the fuel being pumped to the nozzle and the other for the vapor being returned to the storage tank. Although various couplings such as disclosed in U.S. Pat. Nos. 3,171,448; 3,211,178 and 3,513,887 have been suggested in the prior art for use with dual flow path systems, the prior art has not proposed apparatus for coupling portions of such dual passageway fuel lines together for swiveling of the portions relatively to one another and for uncoupling when an excessive tensile force is exerted on the line, and it is clear that the need for such apparatus remains.